1. Field of the Invention
This invention relates to a self-aligning bearing for a precision measurement pendulum.
2. Background Information
A precision measurement pendulum is used to measure the inclination or the vertical position of objects, whereby the angle of inclination can be very small, and the required precision of the inclination measurement very high.
A precision measurement pendulum can be used, among other things, to measure the axis of land vehicles, on which the position of the wheels in relation to one another and the vertical position of the wheels is determined by the deflection of a pendulum against a housing, which is connected to the wheels by means of an apparatus.
Such a precision measurement pendulum, for example, must allow deflections of .+-.11.degree. around its own pendulum axis of rotation. It must also be possible to tip the pendulum by an angle of .+-.15.degree. transverse to the axis, without adversely affecting the precision of the measurement. In many cases, a measurement precision of 20 seconds of an angle is required.
On account of the required high precision of the measurement, and the often unfavorable operating conditions, self-aligning bearings of the prior art cannot be used. Roller bearings are unsuitable, on account of the unevenness of the rolling friction, and a toe bearing cannot be used on account of possible impact loads, and the danger of contamination. Band or tape bearings develop memory effects after long use, if the mounting position differs from the working position.